This invention concerns a system for reversing a reciprocating hydraulic device such as a hydraulic cylinder or a hydraulic motor used for reciprocating motion. The drive circuit for such device employs two hydraulic lines arranged so that when hydraulic fluid is applied to one line and withdrawn from the other the device moves in one direction, and when the direction of flow is reversed the device moves in the other direction. When applied to a pumping system, the invention relates to a pumping element such as a reciprocating diaphragm which is driven by such a self reversing hydraulic system.